Systems and methods for passivation of servo motors

Abstract

Servo motor controls are disclosed for passivation in the event of failures with at least two independent control paths and validation of positional information. A sensor assembly generates signals indicative of the position of the motor rotor, and a signal validation detector is used to validate the generated signals and inhibit rotation of the motor rotor when the sensor assembly generates an invalid signal. A first information processor is provided in communication with the sensor assembly for receiving the generated signals to establish an A Lane decision-making channel control path to the PWM interface, and a second information processor is in communication with the sensor assembly to establish a B Lane decision-making channel control path to the PWM interface. Control logic provided with a PWM interface also inhibits rotation of the motor rotor when a decision from the A Lane differs from a decision from the B Lane. The commutation signal detector provides a state machine to validate the commutation and ensure the validity of signals indicating the position of the motor rotor from the sensor assembly.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to systems and methods for controlling electric motors, and more particularly to controlling a power bridge for brushless, direct current (DC) motors for passivation of servos by inhibited motor rotor operation in the event of a failure.[0003]2. Description of Related Art[0004]In mission-critical applications, and in the aviation industry in particular, there is a need to have mechanical systems fail passively. To this end, motion devices such as electric motors are typically required to stop in their last pre-fault position in a locked state to prevent runaway or positional disturbances and the like in mechanical systems during failure.[0005]Three-phase, brushless, direct current (DC) motors employing conventional designs have been used extensively in servo controls for mechanical systems. A typical brushless servo motor includes a permanent magnet rotor and three-phase stator windings. Th...

AI Technical Summary

Benefits of technology

[0007]The passivation of servo motors is achieved by adding control systems providing plural independent control lanes in the operation of a conventional three-phase pulse width modulated (PWM) servo amplifier, providing that each control lane agrees on the magnitude of current in each phase. The PWM synchronization may be achieved with two independent PWM outputs from each of two channels, A and B Lanes, to control a three-phase power bridge for the DC motor. The PWM frame start is synchronized together by using a common start point, i.e., a clock that initiates the PWM cycle. Each independent control channel of A Lane and B Lane then uses motor rotor positiona

Problems solved by technology

Due to the need to use control electronics to control switching devices, a fault in the motor controller may cause incorrect motor operation, i.e., controller may cause incorrect motor operation, i.e., uncommanded motion.

A failure of a commutation position sensor can cause unwanted movement by energizing the windings incorrectly.

The use of the Hall Effect elements in the motor position assembly in the brushless DC motor may also fail in an unlocked runaway condition because of the control signals required for commutation.

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